Re: [Xen-devel] [PATCH v2 07/20] block/xen-blkfront: split get_grant in 2

[Roger Pau Monnà <roger.pau@xxxxxxxxxx>]

El 09/07/15 a les 22.42, Julien Grall ha escrit:
> Prepare the code to support 64KB page granularity. The first
> implementation will use a full Linux page per indirect and persistent
> grant. When non-persistent grant is used, each page of a bio request
> may be split in multiple grant.
> 
> Furthermore, the field page of the grant structure is only used to copy
> data from persistent grant or indirect grant. Avoid to set it for other
> use case as it will have no meaning given the page will be split in
> multiple grant.
> 
> Provide 2 functions, to setup indirect grant, the other for bio page.
> 
> Signed-off-by: Julien Grall <julien.grall@xxxxxxxxxx>
> Cc: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
> Cc: Roger Pau Monnà <roger.pau@xxxxxxxxxx>
> Cc: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
> Cc: David Vrabel <david.vrabel@xxxxxxxxxx>
> ---
>     Changes in v2:
>         - Patch added
> ---
>  drivers/block/xen-blkfront.c | 85 
> ++++++++++++++++++++++++++++++--------------
>  1 file changed, 59 insertions(+), 26 deletions(-)
> 
> diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
> index 7b81d23..95fd067 100644
> --- a/drivers/block/xen-blkfront.c
> +++ b/drivers/block/xen-blkfront.c
> @@ -242,34 +242,77 @@ out_of_memory:
>       return -ENOMEM;
>  }
>  
> -static struct grant *get_grant(grant_ref_t *gref_head,
> -                            struct page *page,
> -                               struct blkfront_info *info)
> +static struct grant *get_free_grant(struct blkfront_info *info)
>  {
>       struct grant *gnt_list_entry;
> -     unsigned long buffer_mfn;
>  
>       BUG_ON(list_empty(&info->grants));
>       gnt_list_entry = list_first_entry(&info->grants, struct grant,
> -                                       node);
> +                                       node);

Stray change?

>       list_del(&gnt_list_entry->node);
>  
> -     if (gnt_list_entry->gref != GRANT_INVALID_REF) {
> +     if (gnt_list_entry->gref != GRANT_INVALID_REF)
>               info->persistent_gnts_c--;
> +
> +     return gnt_list_entry;
> +}
> +
> +static void grant_foreign_access(const struct grant *gnt_list_entry,
> +                              const struct blkfront_info *info)

Given that this is just a wrapper I would make it an inline function, or
even consider removing it and just call
gnttab_page_grant_foreign_access_ref directly.

> +{
> +     gnttab_page_grant_foreign_access_ref(gnt_list_entry->gref,
> +                                          info->xbdev->otherend_id,
> +                                          gnt_list_entry->page,
> +                                          0);
> +}
> +
> +static struct grant *get_grant(grant_ref_t *gref_head,
> +                            unsigned long mfn,
> +                            struct blkfront_info *info)

Indentation.

> +{
> +     struct grant *gnt_list_entry = get_free_grant(info);
> +
> +     if (gnt_list_entry->gref != GRANT_INVALID_REF)
>               return gnt_list_entry;
> +
> +     /* Assign a gref to this page */
> +     gnt_list_entry->gref = gnttab_claim_grant_reference(gref_head);
> +     BUG_ON(gnt_list_entry->gref == -ENOSPC);
> +     if (info->feature_persistent)
> +             grant_foreign_access(gnt_list_entry, info);
> +     else {
> +             /* Grant access to the MFN passed by the caller */
> +             gnttab_grant_foreign_access_ref(gnt_list_entry->gref,
> +                                             info->xbdev->otherend_id,
> +                                             mfn, 0);
>       }
>  
> +     return gnt_list_entry;
> +}
> +
> +static struct grant *get_indirect_grant(grant_ref_t *gref_head,
> +                                     struct blkfront_info *info)

Indentation.

Roger.


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel